This invention relates to a dual check relief valve for a hydrostatic circuit. Typical hydrostatic circuits use two check relief valves; the first is closed and will act as a high pressure relief valve if the high pressure side of the hydrostatic circuit exceeds the valve setting. The second check relief valve has the check valve open to allow charge flow into the pump. When the pump is stroked to reverse flow, the first check relief valve will open to allow charge flow into the pump and the second check relief will close and operate as a high pressure relief valve.
Though a two valve system is effective in allowing a hydrostatic circuit to function, the manufacturing of two separate valves can cause great cost in the manufacturing process of the valves. Furthermore, because one must machine two different valves in the manufacturing process, this process can take a lot of time. Therefore, it is desired in the art to have a single valve that is able to provide the functionality of the two separate check relief valves in a hydrostatic circuit. By having only a single valve manufacturing costs and time would be greatly reduced.
Therefore, it is a primary object of the present invention to provide a dual check relief valve for a hydrostatic circuit that improves upon the state of the art.
Yet another object of the present invention is to provide a single valve that will provide check and relief functionality for two flow directions in a hydrostatic loop.
Another object of the present invention is to provide a single valve in a hydrostatic loop so that end caps can be smaller.
Yet another object of the present invention is to reduce machining time and cost in manufacturing the hydrostatic pump.
Another object of the present invention is to reduce the cost of providing check relief within a hydrostatic circuit.
A further object of the present invention is to use a dashpot to provide positive dampening of the relief function.
These and other objects, features, or advantages of the present invention will become apparent from the specification and claims.